Normally, a finger-clipped oximeter according to the prior art includes an upper case, a lower case and a pivot which connects the upper case and the to lower case together, and the upper and lower cases apply a clamping pressure to a nail portion of a measured finger through a coil spring. Therefore, the upper case and the lower case can be rotated relatively around the pivot and be separated from each other by a distance.
However, the coil spring which controls the upper- and lower cases is not assembled easily, and is apt to undergo fatigue fracture so that a useful life of the finger-clipped oximeter is reduced.
Additionally, the upper case is connected to the lower case through the structures of the pivot and the coil spring. This kind of connection is neither firm nor reliable. If such finger-clipped oximeter falls off inadvertently, the upper and lower cases may be separated or disengaged from each other.
Furthermore, the upper case is connected to the lower case through the structures of the pivot and the coil spring so that the upper and lower cases move in the directions which are not parallel to each other, thereby, offering a poor comfort to a user in measurement.